The present invention relates to an oral apparatus for use in the treatment of snoring, and particularly to a dental orthosis for use during sleep to treat snoring.
Lay people are commonly familiar with the symptoms of snoring, so little need be said in this regard. In mild cases, it may be a cause of amusement and only minor inconvenience. In more severe cases, however, it can disrupt sleep and even be a manifestation of a serious condition such as obstructive sleep apnea (OSA) syndrome, in which the sufferer must be awakened.
The major methods of treatment and aids to patients with obstructive problems of breathing were developed by Friedrick von Esmarch. As a military surgeon during the many wars in central Europe in the 19th century, he observed that many battlefield deaths occurred due to blood loss and/or strangulation. The principles that he developed to maintain an airway are still the primary principles in use today.
The simple, if somewhat crude, method that he used was to pull the tongue forward and to maintain this position by placing a skewer through the exposed part. This accomplished three major changes that form the principles which he recorded. The tongue was forward and largely clear of the throat, the jaws were open, and the lower jaw was moved forward. These three actions provided a considerable increase in the available airway of the oral pharynx.
Von Esmarch made another oral device which fitted to the teeth of the upper and lower jaw and by using his previously developed principles, this device produced a more open airway without pain or injury to the tongue.
Almost all devices developed and used for this purpose during the twentieth century employ the same basic form and functions of the von Esmarch device. The advent of modern dentistry has permitted refinement and improvements which enhance the aid to the patient with increased tolerance and comfort. There have been many patents issued for devices to help control snoring and obstructive sleep apnea. Most of them follow the von Esmarch principles.
For example, U.S. Pat. No. 1,674,336 to King discloses a respirator which includes upper and lower channels to support the upper and lower teeth respectively. The device is provided with a central air passage which opens into the channels through which air is exhaled. Projections are provided integral with an upper portion of the body of the device, defining between them an air channel. These projections support the tongue so that it does not block the air passages. In practice, this device is ineffective since the position of the tongue is such that the air passages are blocked.
At least one device provides a tongue chamber in front of the mouth. By creating a vacuum in this chamber, the tongue is held forward into the chamber. The device is held in place by fixation to the teeth of the upper jaw. A similar type of device, disclosed in U.S. Pat. No. 4,304,227 to Samelson, includes channels for insertion of the upper and lower teeth and a socket into which the tongue is inserted. The tongue is held in place in the socket. The Samelson device prevents air from escaping from the patient's mouth by a front plate which, when inserted, fits over the exterior portion of the patient's lips. The jaws are locked together during use and the tongue is prevented from resting in its normal position. This type of device may cause problems if the patient's nasal passages are clogged or if the patient coughs or vomits during sleep.
U.S. Pat. No. 4,715,368 to George discloses a device which includes upper and lower channels, including depressions into which the teeth fit. A beak with an orifice at the front end is provided in the center of the mouthpiece which parts the lips to allow air to pass through. The tongue is held in place by flanges extending inwardly from the lower channel. This device has attendant disadvantages in that it locks the jaws together and advances the lower jaw forward causing mandibular repositioning. This causes aggravation of tempo mandibular joint problems and wearer discomfort.
Another type of device is disclosed in U.S. Pat. No. 4,901,737 to Toone. This device is a form of the von Esmarch device but with a marked exaggeration of opening of the jaw wedge. This type of device, which is completely open in the front and preferably open at the top, across the palatal arch, requires mouth breathing, and so causes many complications, such as excess salivation and/or dry mouth. Such a device would be contraindicated in moderately severe or severe OSA. This device locks the jaws together and also repositions the mandible in an open and protrusive position, as compared with the normal closed position of the jaw. This displacement can cause discomfort and aggravate problems with the tempo mandibular joint.
U.S. Pat. No. 5,003,994, issued to Cook, discloses an oral apparatus for reducing snoring and preventing sleep apnea which has a rigid shell with an upper tray, a lower cam structure to advance the mandible structure (lower jaw) forward with respect to the maxilla structure (upper jaw), stops to hold the mouth partially open, and a soft resilient pliable socket inside of the tray. This device is fitted such that the mandible is advanced forward with respect to the maxilla. Thus, this device suffers from the same drawbacks as the Toone device regarding discomfort and potential tempo mandibular joint problems.
U.S. Pat. No. 5,092,346 to Hays et al., provides a dental device which provides a channel for receiving the upper teeth and a ramp formed on the bottom portion to cam the lower jaw forward. The ramp surface engages the lower anterior teeth in a manner such that the lower jaw is moved into a more forward position than normal. This device, by displacing the lower jaw in a more forward position, also causes problems with the tempo mandibular joint and pain and discomfort during use.
Both the Cook and the Hays et al. patents include breathing apertures between the upper and lower channels. These apertures are closed by the natural movement of the tongue during use, thus causing breathing problems.
U.S. Pat. No. 5,117,816 to Shapiro et al. provides an anti-snoring device which includes an upper surface portion which substantially covers all the upper teeth and a lower surface portion which contacts substantially all the lower teeth. An airway passage is provided in the center of the mouthpiece to permit breathing. The device includes a downwardly extending flange intended to extend into the lingual (tongue side of the teeth) vestibule of the user to maintain a forward posture of the lower jaw. This device also may cause pain and discomfort during use due to the forward placement of the jaw.
Though not designed as anti-snoring devices, mouthguards, such as those sometimes used by athletes, provide upper and lower channels into which the teeth are inserted. The pliant material used to form the mouthguards are fitted to the individual by insertion into the person's mouth, after having been heated to soften the material. These devices are not suitable for use as anti-snoring devices since they provide no means by which the tongue is held in a forward position so as to prevent blockage of the esophageal airway. There is no space provided at all sufficient to receive the tongue between the upper and lower channels. Additionally, these devices serve to lock the jaws together and prevent natural movement.
The KLEARAWAY Oral Appliance developed by Dr. Alan Lowe is a device for the treatment of snoring and OSA. However, this device has disadvantages in that it locks the jaws together and advances the lower jaw forward causing mandibular repositioning. This may cause aggravation of tempo mandibular joint problems and wearer discomfort.
In addition to the above mentioned deficiencies, prior devices have also failed to accurately position the maxillary and mandibular teeth in the proper relative positions. Typically, in constructing an oral apparatus, the doctor would have the patient protrude the mandible at the doctor's instructions, which was often not easily controlled, resulting in a misaligned apparatus. If the protrusion was not correct, it would then be necessary to either refit the apparatus to provide the proper positioning or to fabricate a completely new device.